It would have been helpful for us to suggest, if you could have shared the unique index fields ,cursor and insert clause definition.

Doubt: Do you actually want to insert another set of rows with exactly the same values except "ISTC ID" or You wish to update the "ISTC ID" field.

You may think of the following options in case of an update .

1. If you can uniquely identify "ISTC ID" by some filter criteria (using unique index) then u might try directly updating the same.

2. If the above scenario is not possible then u might go for a multi row fetch feature of DB2. This improves the fetch processing by as much as 50%. So, instead of fetching a row at a time you can use multifetch and update the same.

In case of an insert, you might try multi row fetch and multi row insert feature ...not sure how will you handle the duplicates.